brew instal mysql

后报错： ERROR 2002 (HY000): Can't connect to local MySQL server through socket '/tmp/mysql.sock'

执行以下命令解决：（果真又和/usr/local有关）

sudo chown -R _mysql:mysql /usr/local/var/mysql

sudo mysql.server start

来自：https://stackoverflow.com/a/40736952/2193455

接着看： https://flaviocopes.com/mysql-how-to-install/